Tire traction enhancement systems, including those commonly known as tire chains, are used to provide increased vehicle traction during inclement weather, particularly where road conditions include snow and ice. When road conditions worsen to the point that additional tire traction is required to allow a vehicle to continue to safely travel, installation conditions are also typically at their worst. Consequently, one's ability to easily and simply install a tire traction enhancement system becomes extremely important. In addition, to maximize utility of any tire traction enhancement system, it is critical that any vehicle operator whether male or female, young or old, be able to actually install the system, regardless of each individual's level of physical strength.
The configurations of most tire traction enhancement systems currently in use, when outstretched flat on the ground, are ladder-like, incorporating two parallel elongate elements connected by a plurality of transverse traction members. The length of each elongate element is typically the same or slightly less than the tire circumference. The length of each traction member is typically slightly longer than the tire tread width.
The elongate elements and traction members are typically made of flexible material which may include chain, cable, high strength hydrocarbon polymer straps or other similar material. The elongate elements are located on an inboard and an outboard side of the vehicle wheel and serve to draw the traction members tightly against the tire tread.
To install a typical system, two methods are typically used. In one, the entire chain and connector assembly is first draped over the top of the tire. The vehicle is then jacked up until the tire is sufficiently raised to allow the assembly to be wrapped underneath. A connector is then provided to attach ends of the elongate elements together. Alternatively, the assembly is laid flat on the ground in front of or behind the tire and the vehicle rolled slowly over the assembly until both ends of both elongate elements are free and can be connected over a top of the tire. Some systems are configured with continuous elongate elements and no ends (such as Ruhkala, U.S. Pat. No. 2,275,994). Such systems require that the car be jacked up first and then the chains installed from an outboard side of the wheel.
Once the chain assembly has been manipulated to be adjacent the tire and provide access to the ends, the ends are connected to completely encircle the tire. Then, various tightening devices are used to draw the transverse traction members tightly against the tread of the tire. If the transverse traction members are not pulled tightly against the tire tread, the assembly will slip and traction will be lost. In addition, during actual vehicle operation, if slack is still present in the assembly, the traction members will be pulled away from the tire due to rotational centrifugal force. Depending on the amount of slack present, the assembly may damage the vehicle or the assembly itself may be damaged. Hence, it is critical that any tire traction enhancement system be installed tightly at the outset, and, that the tightness be retained while driving.
Current systems typically require a driver to periodically stop his or her vehicle to tighten the assembly to remove any slack which may have developed. In many circumstances, the driver becomes aware that the chain assembly must be tightened by the noise generated when the loose chains slap against the fender well of the car. Unfortunately, damage may have already been caused to the vehicle or the chain assembly. Hence, it is preferable that a system continually remove any slack introduced into the chains during operation to ensure that such damage does not occur.
In most circumstances, vehicle operators will likely find themselves installing a tire chain assembly close to a busy roadside in extremely adverse and dangerous conditions which may include extreme cold, wet, snowy or icy environments. As a result, simplicity and speed of installation is critical. If one's hands are cold or have become numb, installation of a typical traction enhancement system becomes very difficult.
The patent to Ruhkala, identified above, includes a tightening mechanism consisting of a tensioner cable routed through multiple pulleys then attached to a spring. This complex configuration attempts to dynamically increase tension on both inboard and outboard parallel circumferential elongate elements simultaneously. Force is distributed to both sides of the assembly by running a tensioner cable from the outboard pulley system across the tire tread, through another pulley and to other connection points on the inboard circumferential parallel member. The tensioner cable finally terminates by connecting to a metal spring which is attached to the inboard circumferential elongate element. This cable routing increases the difficulty and complexity of installation and subjects the critical tensioner cable to undue wear caused by continual exposure between the tire tread and road surface.
Additionally, because Ruhkala teaches continuous circumferential elements this configuration either requires that the vehicle be jacked up to allow tire chain installation or an awkward process of driving onto the continuous elements of the chains must be performed. Jacking a vehicle off the ground on a roadside in wet, icy conditions where adequate footing may be unavailable creates a very dangerous situation for the party installing the chains. In particular, it is typically necessary to lay flat on the ground and reach behind the tire to make an inboard connection. If the jack happened to slip, the installer could be severely injured, crushed or even killed by the descent of the vehicle on their body. Further, the tensioner spring has a limited range of motion which may be insufficient to remove all slack from the system during operation.
The tensioner system of the present invention is totally contained on the outboard side of the wheel assembly. Hence, the tensioner cable is not subjected to any road wear and installation is simplified. Further, because non-continuous circumferential element chains are used, the vehicle does not need to be jacked up to allow for installation, consequently, the installer's safety is greatly increased. Additionally, the present invention does not require the vehicle to be moved partway through installation to either access connectors or to adjust chain placement on the tire.
Other relevant prior art lacks any means by which the strength of the individual installer can be amplified through mechanical advantage to ease installation while concurrently providing a greater amount of tensioning once installed. In addition, the other relevant prior art does not provide a quick and simple installation system but rather requires various different complex attachment procedures. Finally, the other prior art does not contemplate any means for continuously removing slack which develops during the normal course of operation of a vehicle with tire chains installed.
Accordingly, a need exists for a simple, effective tire traction enhancement system that will operate safely, can be easily installed by individuals with minimal physical strength, will continually seek to self-center the assembly, uniformly distribute assembly weight and continually maintain tension in the tightening mechanism to tightly draw the transverse traction members against the tire tread, even while operating the vehicle.